Disk type grinding apparatus for fibrous materials



May 1, 1956 A. J. A. ASPLUND 2,743,874

DISK TYPE GRINDING APPARATUS FOR FIBROUS MATERIALS Filed July 19, 1952 3Sheets-Sheet l BY rit Y )1 mo HH'orneY May 1, 1956 A. J. A. ASPLUND2,743,874

DISK TYPE GRINDING APPARATUS FOR FIBROUS MATERIALS Filed July 19, 1952 aSheets-Sheet 2 firm juhan Arthur fisplund INVENTOR.

BY {Nb 'Y- M Ht -nq y 1, 1956 A. J. A. ASPLUND 2,743,874

DISK TYPE GRINDING APPARATUS FOR FIBROUS MATERIALS Filed July 19, 1952 3Sheets-Sheet 5 firm Echo Hrflur H s almnd.

INVENTOR.

BY mu Y' "we United States Patent DISK TYPE GRINDING APPARATUSFORFIBROUS MATERIALS- Arne Johan Arthur Asplund, Hoglandet, Bromma, SwedenApplication July 19, 1952, Serial No. 299,878- 7 Claims. (Cl. 241-42)The present invention relates to a grinding apparatus particularlyadapted for operationupon fibrous materials, such as paper pulp, and theapparatus to which the invention has reference is one which includes arotatable disk-like grinding member and a cooperating stationarygrinding member, also of disk-like formation. In a machine of thischaracter, the rotatable grinding member is carried on a shaft that isaxially displaceable or movable to permit of the desired spacing of thegrinding members relative to one another andalso to regulate thecompressive pressure exerted upon the material that is introduced.between said members; The apparatus is primarily intended for operationupon a fibrous material in more or less separated form, for the purposeof sep.-- arating fibre bundles and elfectinga certain disintegration ofthe fibresthemselves. The fibrous material so treated is subsequentlyutilized for the manufacture of paper, pasteboard, fibre board andsimilar products. The ap paratus to be described, however, is: not.limited to suchspecific use since it can also be used for the Working.of many grainy and pulverulent materials.

In order to enable favorable results to be obtained in thedisintegration of fibrous materials, and particularly those which havebeen previously partly separated by steam treatment, it is importantthat the workingv surfaces of the grinding disks be adjusted relativelytoone another with such accuracy that. the deviation from theirparallelism, measured around the circumference, only amounts to one orafew'hundredths of a millimeter. As the disks have a diameter frequentlyamounting to onemeter and the compressive pressure is applied to thefree end of the shaft on which the rotative disk is: mounted, which freeend of the shaft is located at a distance from the disks far greaterthan the diameter of the disks, it will be readily apparent that thisaccuracy with respect to the relative positions of the grinding disksplaces extraordinary demands upon the precision of adjustment of themachine. In practical prior devices the: frame construction of themachine had to be such as to necessitatethe mounting of the hoodenclosing the grinding disks into its position before any fineadjustment of the grinding disks could be effected and this made theadjusting. task exceedingly difiicult.

It is therefore a primary object of the present invention to provide animproved construction for an apparatus. of this character by means ofwhich a more uniformly ground product will be produced.

It is an object of the invention to provide, in an apparatus of thischaracter, means by which the compressive pressure imposed by thegrinding disks shall be produced by operation of a plunger that is:caused to be urged inv either of two directions by a compressive fluidsystem, said plunger being mounted in a stationary housing. A furtherfeature of the invention contemplates the provision of a rotatable shaftmounted in bearings which are axially adjustable to thereby enable therotative grinding disk on said shaft to be adjustedv to or from theSta-- tionary grinding disk in a manner to be explained.

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It. is another object of the invention to provide means by whichthestationary grinding disk is adjustablymount.- ed; to provide an.improved adjustable means for said stationary grinding disk and toprovide housing. structure, shaftesupporting means, and otherconstructional: elements resulting in an improved: apparatus.andadvantageous grinding results.

With the above objects and other objects to be hereinafter set forth, inview, I have devised the arrangement of parts to be described and moreparticularly pointed out in the claims appended hereto,

In the accompanying drawings, wherein apreferred embodiment of theinvention is disclosed,

Fig. 1 is a vertical longitudinal sectional view through an apparatusconstructed according to the invention. and adapted for the working ofpaper pulp;

Fig. 2 is a sectional view taken on the line II--II of Fig. 1, lookingin the direction of the arrows; and

Fig. 3 is a vertical sectional view through that portion of theapparatus shown at the left end of Fig. 1.

Referring to the drawings, 10 indicates a fixed but ad.- justablegrinding disk, and 12 designates the rotatable grinding disk of theapparatus. These disks may be: of any known construction and may beprovided with parallel channeled grinding surfaces 14. The stationarygrind ing disk 10- is'rigidly connected to a support 16 at one end ofthe machine frame, by means of a plurality of circumferentially-spacedbolts 18. The grinding. surface of the stationary disk 10 may beadjusted relatively to. the plane of rotation of. the rotatable disk 12by means of the bolts 20 threadable through the support. 16; In additionto the support. 16,. the frame also includes a second support 22 locatedadjacent to the opposite: end of the frame, the two supports 16 and 22being secured to a bottom plate 28 by means of bolts 24, and being. alsoconnected at the top by a longitudinal tie-bar 30 secured to the twosupports 16 and 22 by means of bolts 26. The rotatable grinding disk 12is detachably securedto a rotor 32, which is in turn secured to a flange34 provided on a shaft 36. The shaft 36 is mounted in two ball bearings38, 40 respectively supported by the bearing, standards 42 and 44secured to and rising from the bottomplate 28. Between the standards 42and 44,. a transmission member such as a pulley 46, is splined on theshaft'36. A bearing housing. 48, enclosing the ball bearing 40,. isaxially displaceable in the standard located remotely from the rotatablegrinding disk 12. In addition to containing the ball bearing 40, thebearing housing 48 contains an axial thrust bearing 50, said thrustbearing. having for its object the transference of thecompressivepressure acting. upon the grinding; disks, from the bearing.housing 48"to the shaft 36.

The fibrous material to be operated upon is-fed into the apparatusthrough a central passage 52 in the support 16, by any suitable meansand preferably by means of the screw conveyor shown at 54. After passingthrough the passage 52,. the material is then moved outwardly betweenthe disks 10 and 12 to the grinding surfaces 14,. to be then collectedafter the grinding operation in a housing 56 out of which. the materialvpasses by way of the outlet 58 shown in Fig. 2. The housing 56 isdivided into twosections in a vertical plane parallel to the axis of theshaft 36. The housing 56 is clearly shown in Fig. 2,- wherein it will beseen that its two sections arev provided at the top with lugs 60 securedto the tie-bar 39 by means of the transverse bolts 62. The support 16has a projection or foot 63 extending between lugs 65- projectingdownwardly from the two sections of the housing 56,. and bolts 64 extendthrough said lugs and through the pro-- jection or foot 63, as clearlyseen in the lower portion of Fig.2. The housing. 56 extends fromthesupport 16 against which it is sealed, and which cooperates with thecasing 56 in constituting a wall of the housing and thus forming anenclosure about the grinding disks 10 and 12. The housing 56 is alsoformed with a boss 56a fitting around the shaft 36. A packing ring 66may be disposed between the shaft 36 and the boss 56a. The tie-bar 30which, during operation of the machine, is subjected to tensile strains,has a cross section relatively large in comparison to its breadth and atthe same time is so shaped as to enable the two parts of the housing 56to be brought into position only after the grinding disks 10 and 12 havebeen mounted and adjusted.

The setting of the grinding disks 10 and 12 of the machine is effectedhydraulically by means of a plunger or piston 70 moved by fluid underpressure, said plunger or piston 70 being mounted in a housing 72extending through an opening in the support 22 and having a flange 75secured to said support 22 by means of bolts '74. he plunger 70 isslidable within a piston-chamber '76 which is internally cylindrical toconform to the plunger 70 and is closed at one end by a cover 78 whilebeing sealed at the other end by the cylindrical extension 80 providedon the plunger, and which has a diameter smaller than the diameter ofthe plunger, and which is slidable through a bore 82 in the housing 72.The plunger 70 is also provided with an axially extended shaft portion84 projecting outside of the housing 72 and being rigidly connected tothe axially displaceable bearing housing 43 by means of a flange 86 andbolts 87. The movement of the plunger 70 in a direction toward thestationary grinding disk 10 is limited by the extension 80 bearingagainst a nut 88 through which shaft 84 is slidable, said nut beingthreaded into the housing 72. The nut 38 is adjustable to a desiredposition and when the desired adjustmeut has been obtained, it is lockedin such position by means of a lock nut 90.

A suction conduit 94 extends from a fluid supply tank 92 for fluid, suchas oil, under pressure. The conduit 94 extends from the tank 92 to apump 96 driven by means of a motor 98. The pressure conduit 10% of thepump 96 opens into a valve housing 1 .12 having a slide valve movabletherein and generally designated at 164. Two conduits designatedrespectively at -6 and 103 extend from the valve housing 102 to theplunger chamber 76 where they respectively open on each side of theplunger 70. The valve housing 102 also has two return conduits 110, 112connected to it and joined together into a common conduit 114 extendingto the tank 92.

The slide valve 104 has three piston portions 116, 118 and 120 having atight sliding fit with the interior surface of the valve housing 102,said piston portions being separated by sections of a smaller-diametershaft while being so arranged relatively to the several conduits thatoil under pressure from the pump 96 will, in re sponse to the positionof the valve, be supplied to the chamber 76 on one or the other side ofthe plunger 70, while oil on the opposite side of the plunger is at thesame time permitted to escape and flow into the tank 92. The valve 104is adjustable from the outside of the housing 102 by means of the button122.

In the position shown in Fig. 3. the pressure conduit 100 is shown incommunication by way of the conduit 106 with the space 76 in housing 72to the left of the plunger 70. At this time there is communicationbetween the space in the housing at the opposite side of the plunger 70and the tank 92 by way of the conduit 108, the valve housing 102 and theconduits 112 and 114. At the same time, the piston portion 116 isshutting off entrance to the conduit 110. Arranged in a conduit 124 thatconnects the pressure conduit 10% with the tank. 92 is a return valve126, which is preferably spring-loaded and adjustable in a known mannerso as to open at a certain maximum pressure. The pressure in'theconduit. 100 may beascertained from a pressure gauge indicated at 128.

When the two disks 10 and 12 are set up against one another, the oilpressure acts on the whole end surface of the plunger 70, whereas whenthe grinding disks are separated from one another, the oil pressure actsonly on the ring surface defined by the difference between the diametersof the plunger 70 and its extension 80. The plunger 70 and its extensiondo not rquire any special packing in their cylindrical contactingsurfaces, but are shaped to secure an accurate sliding fit in theirrespective bores in the housing 72. It is desirable to so arrange thisfit that play will be smaller between the plunger 70 and its chamber 76,than the play between the extension 30 and its bore 82. In spite of thegreater loss through leakage resulting from the looser fit between theextension 80 and its bore 82, it has been found that the plunger 70 maybe moved more rapidly when separating the grinding disks than is thecase when setting them against one another, due to the fact that thequantity of oil under compression required per unit of the length ofplunger movement will be considerably less in the former case. Oilleaking out along the extension 80 is collected in a chamber in thehousing 72 and is returned to the tank 92 by means of the conduit 1.32.

A rod 134 is mounted for axial slidable movement through parts of thehousing 72. Said rod is provided with a projecting arm 136 which is heldagainst the rear end of the extension 80 by means of a coil spring 133in a manner to cause the rod 134 to follow the plunger 70 in its slidingmovements in both directions. A rod 140 is adjustably attached to therod 134 by means of a screw 142. The free end of the rod 140 bearsagainst the movable measuring pointer 143 of a measuring instrument 144.The casing of the measuring instrument 144 has a cylindrical extension145 adapted to be adjusted relatively to the housing 72 by means of ascrew 146 or similar means, in such a manner that the pointer of theinstrument will assume zero position when the working surfaces 14 of thegrinding disks 10 and 12 are in contact with one another. The instrument144 is preferably of such a construction as to permit reading of themovements of the plunger 70 with an accuracy of 0.01 millimeter. Themeasuring range of the instrument 144 comprises approximately theportion of the path of movement of the plunger 70 corresponding to thedistances between the grinding disks 10 and 12 which are typical forcarrying the grinding operations into effect, and during which the arm136 abuts against the extension 80.

It frequently happens that foreign bodies, such as small pieces of scrapiron, stones and the like, find their way into the apparatus and producea rapid increase of the grinding pressure by pressing and holding thegrinding disks apart. To prevent detrimental eifects through too greatstrains caused by such an occurrence, the device includes a safetydevice 147 inserted into a conduit 148 connecting the portion 76 of theplunger chamber on the left of the plunger 70 as shown in Fig. 3, withthe supply tank 92. The safety device 147 may consist of a diaphragmwhich normally completely closes the conduit 148, but which on the rapidcreation of a powerful pressure surge in the chamber 76 of such forcethat the control valve 126 will not have time to equalize it, bursts andrapidly reduces the oil quantity in the chamber 76. The conduit 148 maybe connected to the valve housing 102 by means of a branch conduit 150in such a manner that the liquid pressure produced in the conduit 148slides the valve 104 to the left so as to establish communicationbetween the conduit 106 and the return conduit 112. In order to theninsure the oil escaping past the diaphragm 147 having time toimmediately act upon the valve 104, the portion of the conduit 148between the piston chamber 76 and the conduit 150 is always filled withoil, at least for its greater part. This oil may be supplied from thepressure conduit 100 through a conduit 152 having a cut-off valve 154and a non-return valve 156 arranged therein. The conduit 148 may have anupwardly extending loop 158 preventing the oil located in conduit 148from escaping. Provided on the conduit 148 is an electric release 160,which, upon creation of a pressure surge in the conduit 148 interruptsthe feeding operation into the machine.

Having described one embodiment of the invention, it is obvious that thesame is not to be restricted thereto, but is broad enough to cover allstructures coming within the scope of the annexed claims.

What I claim is:

l. A grinding apparatus for fibrous materials, including a stationarygrinding disk, a rotatable grinding disk for cooperation therewith, therotatable grinding disk being carried by an axially movable shaft tothereby control the spacing of the rotatable disk relative to thestationary disk and to control the compressive pressure exerted by thedisks on material introduced between them, a housing in which a pistonis slidable, a piston in said housing, the piston having an extended endportion located externally of the housing and coupled to the axiallymovable shaft, stop means for limiting the movements of the piston in adirection toward the grinding disks, a fluid pressuse system forintroducing fluid under pressure into the housing at both ends of thepiston, and means for indicating movements of the piston comprising aslidable member mounted on the housing and having a projecting elementin engagement with the piston, spring means for maintaining said elementin engagement with the piston, and an indicating instrument coupled tosaid slidable member.

2. A grinding apparatus for fibrous materials including a rotatablegrinding disk and a stationary disk, a shaft on which the rotatable diskis carried, said shaft being axially movable for the adjustment of therotatable disk relative to the stationary disk and for the regulation ofthe compressive pressure exerted on material introduced between them, aframe having a supporting member at one end, the stationary disk beingadjustable in said supporting member, a support at the opposite end ofthe frame, means at the top and bottom of the supports for connectingthe same, a driving pulley on the shaft, and bearings on the shaft onone side only of the disks, the bearings and pulley being locatedbetween the top and bottom supports of the frame.

3. In a grinding apparatus of the character described, a frame includinga vertical support at each of its ends, a stationary grinding disk, arotatable grinding disk for cooperation therewith, an axially movableshaft on which the rotatable grinding disk is mounted, a two-sectionhousing extending around the disks, one section of said housing having amaterial outlet, one of the vertical supports constituting a wall forsaid housing, said support having an extension, lugs on the sections ofthe housing embracing said extension between them and bolted thereto,the frame including a top bar extending between and connected to thevertical supports, and lugs at 'the top of the sections of the housingembracing said top bar and being bolted thereto.

4. In a grinding apparatus of the character described, including astationary grinding disk, a rotatable shaft carrying a grinding diskrotatable with said shaft, bearings in which said shaft is rotativelysupported, a housing in which one of the bearings is contained, saidhousing being movable in a direction axially of the shaft, said housingcontaining a thrust bearing connected to the shaft, ahydraulically-movable piston having one end attached to the bearing, andafluid pressure system for supplying fluid at either of both ends of thepiston.

5. In a grinding apparatus, a stationary grinding disk, a rotatablegrinding disk for cooperation therewith, a frame including a verticalsupport to which the stationary disk is adjustably secured, a housingenclosing the disks,

the support constituting a wall of said housing, the support having anextended foot to which the housing is attached, the frame including alongitudinally extending tie bar extending between and secured byopposite ends of the frame, and lugs at the top of the housing betweenwhich the tie bar is positioned and to which the tie bar is bolted.

6. A grinding apparatus for fiubrous materials, including a stationarygrinding disk, a rotatable grinding disk for cooperation therewith, therotatable grinding disk being carried by an axially movable shaft'tothereby control the spacing of the rotatable disk relative to thestationary disk and to control the compressive pressure exerted by thedisks on material introduced between them, a housing in which a pistonis slidable, said housing having large and small diameter'parts, thepiston having a part movable in the large-diameter part and havingasmaller-diameter portion slidable through the smaller-diameter part ofthe housing, an extension projecting from the end of thesmaller-diameter part of the piston and protruding out of the housingand connected to the axially movable shaft to thereby transmit theretothe movements of the piston, a fluid pressure system for providing fluidunder pressure within the largerdiameter part of the housing on eitherof the opposite ends of the larger-diameter part of the piston, andmeans in contact with the end of the smaller-diameter part of the pistonand within the housing for reproducing on an indicator the movements ofthe piston.

7. A grinding apparaus for fibrous materials, including a stationarygrinding disk, a rotatable grinding disk for cooperation therewith, therotatable grinding disk being carried by an axially movable shaft tothereby control the spacing of the rotatable disk relative to thestationary disk and to control the compressive pressure exerted by thedisks on material introduced between them, a housing in which a pistonis slidable, the piston having an extension projecting through a part ofthe housing, said extension being connected to the axially movable shaftto thereby transmit thereto the movements of the plunger, a fluidpressure system for providing fluid under pressure within the housing oneither of the opposite ends of the piston, said fluid pressure systemincluding a normally inoperative safety device which becomes operativeupon the creation of extremely high pressure between the grinding disksto thereby open and relieve the liquid pressure in the housing at oneend of the piston, said fluid system also including an emergency valvedirecting in response to its position the fluid to one side or to theother side of thepiston, and a conduit extending from the safety deviceto the said emergency valve and operative upon the operation of thesafety device to cause operation of the emergency valve in a manner torelieve fluid pressure on the plunger.

References Cited in the file of this patent UNITED STATES PATENTS332,234 Case Dec. 15, 1885 614,316 Baker et a1. Nov. 15, 1898 1,146,030Snyder July 13, 1915 1,146,033 Sorensen July 13, 1915 1,570,456 BryantIan. 19, 1926 2,079,882 Traylor May 11, 1937 2,101,442 Martinez Dec. 7,1937 2,156,320 Sutherland May 2, 1939 2,182,900 McIlvried et al Dec. 12,1939 2,338,198 Pall Jan. 4, 1944 2,377,307 Brown June 5, 1945 FOREIGNPATENTS France Mar. 19, 1952

